Device for discharging explosive or combustible charges



July 4, 1939. R. A. coFFMAN DEVICE FOR DISCHARGING EXPLOSIVE 0R COMBUSTIBLE CHARGES Filed Jan. 7, 1935 SSheets-Sheet 1 "I'llll Sheets-Sheet 2 MK LY R. A. COFFMAN Filed Jan.

DEVICE FOR DISCHARGING EXPLOSIVE OR COMBUSTIBLE CHARGES m \N QM July 4, 1939.

lwY rm l a HQ a July 4, 1939. R. A. COFFMAN 2 164;?

DEVICE FOR DISCHARGING EXPLOSIVE 0R COMBUSTIBLE CHARGES Filed Jan. '7, 1935' 3 Sheets-Sheet 3 Patented Jilly 4, I939 UNETE DEVICE FOR DISCHARGING EXPLOSIVE O COMBUSTIBLE CHARGES Roscoe Alexander Coffman, Pittsburgh, Pa. g

- Application January 7, 1935, Serial No. 751 I 16 Claims. (Cl. 123-483) This invention relates broadly to a device for discharging explosive or combustible charges.

35 firmly locked in position against the open end of the barrel; v

Another object. of the invention is to provide a device ofthis character with means to vent back pressures and gases from the cartridge barrel 20 so that the breech blockmay be opened without danger'of a forcible ejection of theempty cartridge;

Another. object of the inventionis to provide a device for electrically. igniting a charge in v 25 which the electricalcircuit is always broken when the device is open for the insertion of avcharge.

Another object of the invention is to provide a device of the character to be described in which the firing pin cannot be brought into contact '30 with a cartridge with suflicient force to mutilate the same.

Other and important objects of this invention will become apparent as the following description is read in connection with the drawings herein: 35 Fig. 1 is a side elevation of the device with the breech block closed and in locked position and with its associated vent closed,

Fig. 2 is a view similar to Fig. 1 in which thev breech block is shown in its open position with 49 its associated vent open and in which a portion of the breech block is broken away to show cer- 55 Fig. 5 isa horizontal, sectionalview taken on' locked in closed position and with the associated line 5-5 of Fig. 3 and shows someparts in eleva- Fig. 6 is. a vertical sectional view taken on line 6'6.of Fig. 3,

Fig. 7 is a vertical sectional view taken on line 5 1-1 of Fig. 3 and showing some parts in elevation, and l Fig. 8 is a vertical sectional view taken online 8--8ofFig.3. a

While this'invention may be applied to a wide 10 variety of uses, nevertheless for convenience of description and illustration it will be described as being used in connection with the aeroplane starting motor of myapplication, Serial ,No. 536,389 wherein I have shown a motor which is operated by propulsive gases produced by an electrically discharged cartridge, as shown in myl ap-,

'plication, Serial No. 581,032;

' Referring more in detail to thefdrawingsdn which like parts areindicated by like reference numerals throughout tl'iefseveral figures, my invention comprises a barrel "l0 or other convenient means forholding 'a cartridge or other explosive or combustible charge, provided at one'end with screw threads H for attaching the same to. my

aeroplane starting system or other device (not shown). The other or rear end of the barrel I0 is closed by means of the breech block l2, and the barrel I0 and breech block l2 are supported by a plate l3 by means of which the device may conveniently be attached to a control board of an aeroplane or to some other support atlits point of use by means of screws or other suitable means.

The barrel I0 is provided with a bore It adapted as to hold a cartridge l5 or other suitable explosive or combustible charge. At the rear end of the bore I4 is provided a recess I6 against which the shoulder of a cartridge l5 may rest. On the underside of the barrel l0 and formed integrally 40 therewith, is 2. lug H in which is formed a bore l8 'for accommodating ashell extractor l9. A second bore 20 is formed directly under. bore l8 and accommodates a breech locking pin 2|. The front end of lug I1 is formed with a circular recess- 22 which is adapted to accommodate alocking-post 23 with which is formed extending at right angle thereto": an operating lever 32 by means of which the locking post 23 'may be rotated. Q 1

Pivoted on and moving angularly about locking post 23 is the breech block l2.

At the fore end of barrel!!! is a vent 24, closed by means of a valve mechanism 25. The valve mechanism 25 is operated through an operating rod 25, which lies in contact with locking post 23.

The locking post 23 is provided with a cam recess 21 against which the head 28 of the locking pin 2| is pressed by means of a coil spring 35, which spring is held under tension between the head 25 of locking pin 2| and a shoulder 3| in bore 25. When the operating lever 32 is in its raised or vertical position the cam surface 21 of the locking post 23 faces rearwardly, and the coil spring 35 therefore urges locking pin 2| into the cam recess. In this position the locking pin 2| is located entirely within the lug l1 and the breech block |2 may therefore be raised and lowered at will.

The breech block |2 which moves angularly about the locking post 23 to close or open the barrel ||l, carries interiorly the mechanism for firing the shell |5. This mechanism will now be described. Within the breech block l2, which is suitably recessed, and resting against the face plate 33, which is attached to the breech block |2 in a suitable manner as by screws (not shown) is a block of insulating material 34 in which is guided for horizontal reciprocatory motion an operating plug 35 and a firing pin 35. The operating plug 35 and the firing pin 35 are connected by means of a fulcrum lever 31 which is movable around a pivot pin 35, supported in the sides of the insulating block 34, and located centrally of the length of the fulcrum lever 31. One end 35 of the fulcrum lever 31 operates in a recess 45 in the operating plug 35, while the other end 4| operates in a recess 42 in the firing pin 35.

The operating plug 35 is urged forwardly as shown in Fig. 3 by means of a coil spring 43, which is retained at its one end by a shoulder 44 on the operating plug 35, and at its other end in a suitable recess in the back plate 45. When in this position the fulcrum lever 31 is turned about its pivot 35 and the firing pin 35 is drawn rearwardly, as shown in Fig. 3 by virtue of contact between the end 4| of the fulcrum lever 31 with a bolt 46 at the rear end of the firing pin. Forming an electrical contact with the firing-pin 35 is a conductor 41, one end of which is securely clamped to the bolt 45 by means of a nut 45. The other end of the conductor 41 is in electrical contact with a contact 49 in the bottom of the insulating block through clamping nuts 50 and 5| on the screw threaded end 52 of the contact 45 which extends through the insulating block 34.

The firing pin 35 is provided with a recess as shown at 42, and is provided with a contact point 53 adapted to make electrical contact with the shell |5. Within the recess 42 of the firing pin 35 is a coil spring 54, one end of which is in contact with the forward end of the firing pin and the other end of which is closed by a pressure button 55, against which the end 4| of the fulcrum lever 31 rests.

The insulating block 35 is securely held within the breech block l2 and against the face plate 33 by means of screws 55 (Fig. 6). The open rear end of the breech block I2 is closed by means of a closure plate 45 which is preferably formed of insulating material and which is held securely in place by means of a plurality of screws such as shown at 51 and preferably by at least one additional screw 58 which cooperates with a stud head of the screw 55.

Electrical contact 45 which is carried by the insulating block 34 and which is adapted to move with the breech block l2 contacts, in its closed position, with a fixed contact 55 untried by the plate I3 and insulated therefrom by an insulating strip 60. This contact is connected with a source of electric current by means of a connector 5| attached to the contact 55 by means of a terminal 52 passing through the plate l3. For this purpose insulating washers 53 are provided and between which the conductor 6| is clamped by means of nuts 54 screwed to the end of the terminal 52.

It may now be noted that the plate I3 is firmly attached to the lug H of the barrel II by means of a screw threaded bolt 55.

The vent 24 of the barrel l5 has heretofore been mentioned and the valve mechanism for opening and closing this vent will now be more particularly described. The valve mechanism 25 isscrew threaded as at 55' to engage screw threads in the barrel vent, or otherwise suitably attached to the barrel ID. This valve mechanism is provided with an exhaust bore 55 through which gases may pass when the bore 55 is uncovered. In order to close the exhaust bore 55 the valve mechanism is provided with a valve stem 51 on the end of which is formed a head 55, a portion of which is conically shaped to fit snugly into a seat 55. The valve stem 51 is urged rearwardly by means of a coil spring 15 and consequently the head 55 is urged into the seat 55 to close the exhaust port 55. This spring rests against a shoulder 1| on the exterior of the valve body and is enclosed by a sleeve 12 which slides upon a suitably formed face 12' of the valve body and against which the rear end of the coil spring 15 rests. The sleeve 12 may be restrained in its rearward movement by means of a cotter pin 13 or by other suitable means. The valve stem 51 rests loosely in a sleeve 14 which is carried by the operating rod 25 and which may be attached thereto by means of a pin 15 passing therethrough. The sleeve 14 may, however, rest loosely between the valve stem 51 and the operating rod 25 to maintain the two in alignment, but to provide at the same time means for quickly disconnecting the two. The operating rod 25 passes through the plate l3 and lies in contact with the locking post 23 which post is provided with a slot 15. This slot assumes a vertical position when the locking lever 32 is in closed or locking position, thus permitting the end of the operating rod 25, urged by the coil spring 10, to enter the recess 15 and permit the valve head 55 to close the exhaust port 55. The valve mechanism 25 may be provided with a screw threaded closure plug 11 for the purpose of cleaning, lubricating, or inspecting the interior of the va ve.

The shell extractor I9 is formed with a lip 15 against which the head of the shell |5 may rest, and which is adapted to engage behind the shell head to extract the same when the extractor I5 is moved rearwardly by means of the finger 19 operating against the rear of the extractor l5 and through a transverse slot 55 in the lug l1. The finger 15 is a horizontal extension of a plate 5|, Figs. 2 and 8, which is pivoted to the lug H by means of a screw 52. This plate is thrown forward into engagement with the extractor I5 through engagement with a snail 53 formed on the interior of the breech block l2. The extractor IQ is held within its bore by means of a transverse member 54 which lies in a slot formed in theextractor l5, and which is held in position preferably by means of a cotter. pin 85. Fig. 2.

It will be noted that the breech block I2 is formed on an are 51 at its lower corner which contacts the plate l3, thus permitting free movev 2,164,700 .ment about the locking post 23. The breech block is also provided with a stop pin 88 for the purpose of limiting the downward movement of operating lever 32.

Assuming now that a shell has been fired and it is desired to eject the empty cartridge, insert another, and fire the same, after a discharge the operating lever 32 is thrown to its vertical position and the locking post 23 is rotated through a part of a revolution, causing the end of the rod 25fto ride upon the cylindrical surface of the locking post, thus moving the valve stem 61 forwardv against the tension of the spring 10, moving the valve head58away from its seat 69 and opening the exhaust port 66 while the breech block itself is still in. closed position. This -operation permits gases within the barrel II) to vent to the atmosphere and release any back pressures within the barrel so that when the breech block l2 is'lowered, the shell l5 within the barrel ID will be not forcibly ejected. At the same time the head 28 of the locking pin will have entered the cam recess 21 of the locking post 23 under pressure of the spring 30 and the locking pin 2| will be completely withdrawn from the face plate 33 and will now lie entirely within the lug H. The withdrawal of the locking pin 2| will permit the operating plug 35 to move forward under the action of the coil spring 43, thus turning the fulcrum lever 37 about its pivot 38 and thereby withdrawing the firing pin 36 out of contact with the shell in the barrel I0.

Now the breech block I 2 may be permitted to fall to its open position as shown in Fig. 2, thus breaking contact between the contact members 49 and 59. At the same time the snail 83 will contact the plate BI and move it around its pivot 82, thus moving the horizontal extension 19 against the front of the extractor l9 and moving the same rearwardly. Since the lip 18 of the extractor i9 is in engagement with the rim of the shell IS the shell will be moved rearwardly out of the barrel ID, to an extent sufficient to clasp the same with the fingers to completely withdraw it from the barrel.

A new shell may now be inserted into the barrel l and moved forward into engagement with the lip 18 of the extractor [9, thus moving the extractor l9 forward when the breech block I2 is raised sufficiently to bring the snail 83 out of contact with the plate 8|. It will be noted that at this time the contacts and 59 are still apart, thus avoiding possibility of short circuiting through the breech block l2. When the breech block I2 is raised to the position shown in Fig. 3, electrical circuit is made through the contacts 43 and 59 to the contact point 53 of the firing pin 35, but the firing pin 35 is held withdrawn into the insulating block 33 by force of the coil spring 43, and can thereforenot contact the "cartridge l until further operation of the operating lever'32. Whenv the operating lever 32 is now brought down into its horizontal position, the locking post23 will again be rotated to'per- .mit the end ofthe valve operating rod 26 to ride in itsslot lli of the locking post 23, thus permitting the valve stem 51 'to move rearwardly under tension of the coil spring and permit the valve head'68 to seat in its valve seat 69 and close the exhaust port 66. At the same time, or preferably slightly thereafter, the cam recess 21 of the locking post 23 will have 'been moved away from the head 28 of thejlocking pin 2|, and the head 28 of the locking pin 2| will then be in engagement with a higher cylindrical portion of the pin 2| will be moved rearwardly against the tension of the coil spring 30, and will move into the recess in the face plate 33. It may be .specifically noted that rearward movement of the'locking pin 2| will :carry with it thefulcrumoperating butten 35 by virtue of contact between these two members, and further, that the locking pin 2| will have moved into the face plate-33 'to securely lock the breech block l2 to the barrel before the firing pin 33 has moved forward any appreciable distance. This assures afirm lock between the breech block l2 and the barrel IU-prior to contact between the firing point 53 and the shell l5.

c As the locking, pin 2| continues to move rearwardly the operating button 35. will be moved with it against tension of thecoil spring 33, thus moving the fulcrum lever 3'! .around its pivot 38 and end 4| of fulcrum lever 3'| forward against tension ofthe-coil spring'53. The firing pin 36 will now move forward bringing the firing point 53 into contact with the shell l5, and when this contact is made the shell IE will be discharged, the electrical circuit having been completed through the conductor 6|, contacts 59 and 49, conductor 41, and the firing pin 35. It will be noted that the movement of the firing pin 33 is greater than the movement necessary for contacting an electrical contact in the shell l5. When the firing point 53 is in contact with the shell IS, the spring 56 serves as a lost motion or take up device which compensates for the balance of the movement of the fulcrum lever 31. If an ordinary shot gun shell with a percussion cap or primer were to be placed in the barrel Hi, the firing point 53 upon contact with the percussion cap of the shell would stop moving forward and the spring 54 would absorb the balance of movement of the fulcrum 3'! to prevent the firing point 53 from sinking into the percussion cap, thus making it impossible to fire the, percussion cap shell in the barrel.

This describes a complete cycle of operation and it is of course to be understood that each subsequent operation of the device will be similar. It has been the object to describe this invention in general terms to avoid limitations which are not intended to be implied into the claims hereinafter appended. Particularly with reference to the term explosive charge or cartridge, it is to be noted that any combustible charge is intended and the particular form of the charge is immaterial in so'far as this invention is concerned. The drawings, in view of which this description has been written, are used for convenience in illustrating one form of the invention only, and it is expressly to be understood that various modifications and changes may be made within the scope of the following claims, am what I claim is:

1. In a device of the class described, a barrel adapted to hold an explosive cartridge, 2. pivoted breech block for'closing one end of said barrel, a firing pin in said breech block, an electrical contact fixed to said barrel structure exteriorly of said breech block, an electrical connector for said pin in said breech block and movable therewith to engage said contact in only the closed position of said pivoted breech block, a single means operable upon initial movement thereof to lock said breech block to said barrel in closed position, and. upon further movement thereof 7 move said firing pin into operative relation with a cartridge in said barrel.

locking post 23. Under this action the locking provided with a vent and adapted to hold an explosive cartridge, a pivoted breech block for closing one end of said barrel, a firing pin in said breech block, an electrical contact fixed to said device exteriorly of said breech block, an electrical connector for said pin in said breech block and movable therewith to engage said contact in only the closed position of said breech block, means operable upon initial movement thereof to close said vent in said barrel and to lock said breech block to said barrel in closed position,

and upon further movement thereof move said firing pin into operative relation with a cartridge in said barrel.

4. A device of the class described comprising an open ended barrel adapted to hold an explosive cartridge, a breech block for closing one end of said barrel, a locking post about which said breech block is pivoted, a locking pin movable by said post for engaging said breech block in closed position, a firing pin carried by said breech block adapted to be moved into firing position by said locking pin, an electrical contact fixed to said barrel, an electrical connector for said pin fixed to said breech block adapted to engage said contact in only the closed position of said breech block, a vent for said barrel operable by said locking post, and a shell extractor operable upon the movement of said breech block.

5. A device of the class described comprising an open ended barrel provided with a vent and adapted to hold an explosive cartridge, a breech block for closing one end of said barrel, a locking post about which said breech block is pivoted, a locking pin in contact with said post adapted to engage said breech block in closed position, a vent closure in contact with said post, a firing pin operable by said locking pin carried by said breech block, a fixed electrical contact exterior to said breech block, 'an electrical connector fixed to said breech block and movable therewith to engage said contact in only the closed position of said breech block, means to rotate said locking post to lock said breech block to said barrel in closed position and move said vent closure to closed position upon initial rotation, and upon further rotation move said firing pin into operative relation with a cartridge in said barrel.

6. In a device of the class described, a barrel provided with a vent and adapted to hold a combustible charge, a breech block adapted to close one end of said barrel, a locking post associated with said barrel and adapted for locking said breech block to said barrel, and a valve operable by said post to close said vent upon the initial movement of said locking post.

7. In a device for igniting a combustible charge, a barrel provided with a vent, a movable locking post associated with said barrel, a breech block adapted to close one end of said barrel, a

locking pin operable by said post for locking said breech block in closed position, a valve operable by the initial movement of said post to close said vent, said post upon further movement operative to move said pin to a position to lock said breech to said barrel.

8. In a device of the class described, a barrel provided with a vent and adapted to hold an explosive cartridge, a breech block for closing one end of said barrel, a firing pin in said breech block, means operable upon initial movement thereof to lock said breech block to said barrel in closed position, and upon further movement thereof move said firing pin into operative rela-- tion with a cartridge in said barrel, the said means operable to lcck said breech block simultaneousiy permitting automatic spring actuated closing of the vent in said barrel.

9. In a closed system for igniting a combus tible charge, a barrel adapted to hold a combustible charge, a breech block adapted to close one end of said barrel, a firing pin for said combustible charge, means operable to lock said breech block to said barrel in closed position,

and means for preventing the unlocking of the breech block prior to the releasing of the pressure within the system.

10. In a closed system for igniting a combustible charge, a barrel adapted to hold a combustible charge, a breech block adapted to close one end of said barrel, 'means operable to lock said breech block to said barrel in closed position, an electric firing pin carried by said breech block and adapted to contact said c:mbustible charge for igniting the same when the breech block is locked, and means for releasing the pressure within the system after firing of the cartridge within the system and prior to the unlocking .of the breech block.

11. In a closed system in which fiuid pressure is generated for use in performing a work operation, a barreladapted to hold an explosive cartridge, a breech black adapted to close one end of said barrel, a firing pin in said breech block, a single means operable upon initial movement thereof to lock said breech block to said barrel in closed position, and upon further movement thereof move said firing pin into operative relation with a cartridge in said barrel, means for firing said cartridge, and auxiliary means for releasing the pressure within the system after firing of the cartridge and prior to the unlock-r ing of the breech block.

In a closed system in which fluid pressure is generated for use in performing a work operation and including a cartridge receiving barrel chamber, a breech block adapted to close one end of said barrel chamber, means for locking said breech block in operative relation with the barrel chamber, means for firing a cartridge within said barrel chamber, and means controlled by the locking means for releasing the pressure within the closed system prior to the unlocking of the breech block.

13. In a closed system in which fluid pressure chamber, a breech block adapted to close one end of said barrel chamber, means for locking said breech block in closed position, venting means for said closed system, and means requiring the operation of the venting means for the purpose of releasing the pressure within the system prior to the unlocking of the breech block.

15. In a closed system in which fluid pressure is generated for use in performing a work operation and including a cartridge receiving barrel chamber, a breech block adapted to close oneend of said barrel chamber, mechanism for locking said breech block in closed position, venting .mechanism for said closed system, and a single manually operated means cooperating with both the locking mechanism and the venting mechanism requiring the operation of the venting mechanism for the purpose of relieving pressure within the closed system prior to the unlocking of the breech block.

16. Ina closed system in which fluid pressure is generated for use in performing a work operation, an open ended barrel provided with a vent independent of the muzzle of said barrel and adapted to hold an explosive cartridge, a breech block for closing one end of said barrel, means for locking said breech block in closed position, 'a vent closure, and means operable to open said vent for releasing the pressure within the closed system prior to the unlocking of the breech block.

ROSCOE ALEXANDER COFFMAN. 

